These are the berries I'm looking at as well. Ill check in to the muscadines and see how they will do in my area.

What's general time frame before you see fruit from these guys? 2 years ?

2 years you will see fruiting

Make sure to prune your muscadine in January or February. I just pruned mine back. They will produce better fruit. You want one main trunk and two off branches at the top. Looks like a Power T. Cut back every year

Blackberries you want to cut out the dead canes every year. You can dig up off shoots and replant. I usually take one cane that bends to the ground and bury it on the end, with the last few inches sticking out of the ground. I do this in the fall and leave them all winter. This will root and in the spring, you transplant it to get a new plant.

I actually had one of my muscadines root like this fall. I will dig it up and move it this spring